I agree with the "cars are not stuck in traffic, they are the traffic" thing, but I think it can be unfair when you make the subject people.

I am currently lucky enough that I can take the train to and from work. Never have to get on the asphalt on my commute except to cross the street twice. It's great. I sit down and it goes. Lovely stuff. This hasn't always been the case, though. My car was my one and only option at my previous workplace. Way too far to bike, no public transport, so I was forced to drive there. I hated every minute of being one of the many single-occupant cars on the road. I'd very much have liked to not be sitting in front of a steering wheel believe you me, but the city simply did not provide any better alternatives. I argue that I was stuck in traffic because I didn't choose to be there in a car to begin with. And that most definitely did get on my nerves quite often, and it did make me more irritable.

Yeah yeah people could and should vote for politicians who'll build that infrastructure, but until those are elected and that infrastructure has been built, there are plenty of people who are stuck in traffic.